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Direct numerical simulation of a turbulent flow over an axisymmetric hill

Castagna, Jony; Yao, Yufeng; Yao, Jun

Authors

Jony Castagna

Yufeng Yao Yufeng.Yao@uwe.ac.uk
Professor in Aerospace Engineering

Dr Jun Yao Jun.Yao@uwe.ac.uk
Senior Lecturer Aerospace Themofluids



Abstract

Direct numerical simulation (DNS) of a turbulent flow over an axisymmetric hill has been carried out to study the three-dimensional flow separation and reattachment that occur on the lee-side of the geometry. The flow Reynolds number is Re H=6500, based on free-stream quantities and hill height (H). A synthetic inflow boundary condition, combined with a data feed-in method, has been used to generate the turbulent boundary layer approaching to the hill. The simulation has been run using a typical DNS resolution of δx + = 12.5, δz + = 6.5, and δy1+=1.0 and about 10 points in the viscous sublayer. It was found that a separation bubble exists at the foot of the wind-side of the hill and the incoming turbulent boundary layer flow undergoes re-laminarization process around the crest of the hill. These lead to a significant flow separation at the lee-side of the hill, where a very large primary separation bubble embedded with a smaller secondary separations have been captured. The present low-Re simulation reveals some flow features that are not observed by high-Re experiments, thus is useful for future experimental studies. © 2014 Elsevier Ltd.

Citation

Castagna, J., Yao, Y., & Yao, J. (2014). Direct numerical simulation of a turbulent flow over an axisymmetric hill. Computers and Fluids, 95, 116-126. https://doi.org/10.1016/j.compfluid.2014.02.014

Journal Article Type Article
Acceptance Date Feb 11, 2014
Publication Date May 22, 2014
Journal Computers and Fluids
Print ISSN 0045-7930
Publisher Elsevier
Peer Reviewed Peer Reviewed
Volume 95
Pages 116-126
DOI https://doi.org/10.1016/j.compfluid.2014.02.014
Keywords turbulence simulation, 3D flow separation
Public URL https://uwe-repository.worktribe.com/output/817412
Publisher URL http://dx.doi.org/10.1016/j.compfluid.2014.02.014

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